Waste disposal unit



June 25, 1968 s. F. TOPINKA 3,389,864

WASTE DISPOSAL UNIT Filed Dec. 10, 1965 2 Sheets-Sheet 1 A TTORNE Y8 6 age "T M J 2924.1, m,mzq

June 25, 1968 G, TQPINKA 3,389,864

WASTE DISPOSAL UNIT Filed Dec. 10, 1965 2 Sheets-Sheet 2 I INVE/V r011?- Gemge {a 3 2M, m-J,

A TTORNEYS United States Patent 3,389,864 WASTE DISPOSAL UNIT George F. Topinka, Riverside, Ill., assignor to FMC Corporation, a corporation of Delaware Filed Dec. 10, 1965, Ser. No. 513,043 8 Claims. (Cl. 241-441) ABSTRACT OF THE DISCLOSURE The waste disposal unit comprises a hopper for receiving waste and a pair of comminuting units blocking the open bottom of the unit so that all of the waste material deposited in the hopper must pass through one of the comminuting units before it can pass through the open bottom of the unit. One of the comminuting units is slightly lower than the other, and the direction of rotation of the cutting cylinders causes the waste material to move toward the combs of both cylinders. Water jets are mounted at opposite ends of the comb of the lower unit. The units comminute waste only when the cylinders are rotating in one direction, and when the direction of rotation is reversed the water jets wash the residual waste from the lower cylinder.

This invention relates to a Waste disposal unit, and is particularly concerned with a structure adapted for use in a hospital or similar institution to comminute waste.

Hospitals usually dispose of their waste by comminuting it and then flushing it into a drain. Heretofore, hospitals have encountered considerable difliculty in comminuting waste comprising fibrous nonwoven fabric because such material has no shear strength, and conventional comminuting operations often do no more than to merely separate the fibers without cutting them into fragments. Such fibers have a tendency to bunch on the cutting cylinder, and eventually jam the comminuting apparatus.

The waste disposal unit of the presentinvention comprises a hopper having an open bottom in vertical registration with an open top discharge means, preferably in the form of a flushing bowl, and an open ended housing between the hopper and the discharge means. A plurality of comminuting units extending transversely of the housing block the open top of the bowl to prevent waste dropping from the hopper from falling directly into the bowl without passing through one of the comminuting units. The comminuted waste is flushed from the bowl into a drain. Each comminuting unit comprises a cutting cylinder provided with hook-shaped teeth projecting from its peripheral surface, and a comb cooperating with the teeth of the cutting cylinder to comminute waste engaged by the teeth and the comb when the cylinder is being rotated in one direction. The cutting cylinders are rotated in the same direction for a predetermined time interval to comminute a quantity of waste, and then are reversed to rotate in the opposite direction for a considerably shorter time interval to allow water jets to clean the comb.

A plurality of water jets are positioned to clean the combs of the comminuting units and to facilitate the movement of the waste through the hopper into engagement with the cutting cylinders. The cutting cylinder mounted closest to the front wall of the waste disposal unit is journaled in a lower horizontal plane than the other cutting cylinder. The upper cutting cylinder and the comb of the lower cutting cylinder are in the same general direction relative to the axis oft he lower cutting cylinder. The direction of rotation of the cutting cylinders causes the teeth of the lower cylinder to move the waste on said cylinder toward its comb and the upper cylinder. The comb of the lower cylinder extends transversely of the housing in alignment with the open bottom 3,389,864 Patented June 25, 1968 "ice of the hopper and the open top of the discharge means. Water jets are mounted at opposite ends of the comb of the lower cylinder and are directed to throw streams of Water longitudinally of the comb to wash residual waste from it. The waste that is not engaged by the comb of the lower cylinder is moved toward the upper cylinder. The teeth of the upper cylinder carry the waste engaged thereby toward the comb of the upper cylinder where it may be comminuted. I

g The upper cutting cylinder is positioned directly below the vertical wall section at the rear of the hopper, and its comb is'aligned with the vertical wall section. One of the water jets is di ected to throw a stream of water downwardly along the vertical wall, and its stream engages the comb of the upper cylinder to wash residual waste from it and thereby keep it clean to facilitate comminution of the waste. This jet stream drives some of the waste down ward toward the lower cylinder against the action of both cutting cylinders that are moving some of the waste toward the comb of the upper cylinder. The combined action of the teeth of the lower cylinder trying to move waste to the upper cylinder, and the jet stream trying to move waste from the upper cutting cylinder to the lower one, induces a rotary motion in the Waste in the area above the comb of the lower cylinder. The direction of this rotary motion is opposite the direction of rotation of the cylinders, and the waste so rotated presents a constant changing surface to the action of the teeth of both cutting cylinders.

The teeth of the cutting cylinders cut only when the cylinders are rotating in one direction. During the cutting action of the cylinders, the comminuted waste falls into the discharge means. However, some of the small particles of comminuted waste become suspended in the mix ture of water and waste being rotated in the area above the comb of the lower cutting cylinder. When the direction of rotation of the cutting cylinders is reversed, some of this comminuted waste drops through the gaps mentioned above into the flushing bowl, and the water jets clean the residual waste from the combs. This residual waste also drops through the same gaps into the flushing bowl. A pair of water jets is provided in the flushing bowl to induce a swirling action that facilitates flushing the comminuted waste into a drain.

Suitable structure by means of which the above mentioned and other advantages of the invention are attained will be fully described in the following specification, taken in conjunction with the accompanying drawings showing a preferred embodiment of the invention; in which:

FIGURE 1 is a perspective view, on a reduced scale, of a. waste disposal unit embodying the invention;

FIGURE 2 is a vertical sectional view of the unit;

and

FIGURE 3 is a horizontal sectional view, taken along the line 3-3 of FIGURE 2.

In the drawings, a cabinet 11 serves as a supporting frame for a hopper 12, a housing 13 in which comminuting units are mounted, and a discharge means 14. The housing 13 may be integral with the hopper 12, if desired, but is preferably a separate member to facilitate disassembly when the comminuting units need servicing. The cabinet also supports a reserve water tank 15 and a motor 16. The cabinet comprises a base 17, vertical uprights 18, horizontal braces 19 reinforcing the uprights, a top member 21 supported on said uprights, and side panels 22 removably secured to the uprights 18 below the top member.

The top member 21 is closed on four sides, but is open at its bottom and is provided with flanges 23 defining an opening 23 in its top wall. The upper end of the hopper 12 is supported within the top member 21 byflanges 24 thatare seatedonthe flanges 23. They open top of the hopper, into which the waste is fed, is closed by a cover 25 hinged to the top member along one of the edges defining the opening 23'. T he cover is pre-fer ably provided with a suitable electrical interlock switch (not shown) to prevent operation ofthe apparatus when the cover is open. A control panel 26 rnounted in the top member 21 controls, the normal operation of the waste disposal unit. The cover 25 is lifted about its hinge to provide access to the hopper 12. p

The hopper 12 has an inclined frontwall ,27 and a back wall 28 comprising an inclined upper wall section 29 extending downwardly from the flange 24 and;a vertical lower wall section 31. The vertical wall section 31 terminates at its lower 'end in a. horizontal flange .33, and the front'wall 27 terminates in a flange 33' coplanar with flange 33. Each sidewall 34 of the hopper is-provided with a flange 35 at its upper end. The flanges 35 cooperate with the flange 24, and aprojection .36 extending along the upper end of front Wall 27, to support the upper end of the hopper. The lower end of the hopperis supported. on the top of a housing 13. The housing 13 for supporting the comminuting units is preferably in the form of a casting 37 open at its top and bottom, and having lateral flanges 38 and 39. The flanges 38 and 39 are seated on the horizontal braces 19 of the cabinet 11 to support the casting. The top of the casting has two flanges 32 and 32' which serve as supports for the flanges 33 and 33', respectively, at the bottom of the hopper. The housing 13 supports a lower cutting cylinder 41 and an upper cutting cylinder 42. The cutting cylinders are journaled inbushings 43 mounted in the sidewalls 44 of the housing 13, as shown in FIGURE 3. Each cutting cylinder comprises a core 45 and a plurality of longitudinally spaced disks 46 having hook-shaped teeth 47 projecting from their outer edge. Each cylinder also has two or more shear bars 48 secured thereto, preferably at diametrically opposite points. The shear bars cooperate with the portions of the outer edges of the comb between the notches to facilitate comminution of waste that extends across two adjacent notches. A suitable drive mechanism, such as that indicated at 49 in FIG. 3, connects both cutting cylinders to the motor 16.

The lower cylinder is provided with a support bar 51 extending transversely of the housing 13 in the area be tween the cutting cylinders 41 and 42. The bar 51 is supported at its ends in any suitable manner. The longitudinal edges of the bar 51 are spaced so closely to the peripheral surfaces of both cutting cylinders that no uncomminuted waste can pass between the support bar and adjacent cutting cylinders. The peripheral surface of the cylinder 41 is spaced so closely to the front Wall of housing 13 that no uncomminuted waste can pass through the gap between the cylinder 41 and the front wall of the housing. A comb 52, mounted on the support bar 51 and projecting therefrom, is provided with notches 53 on one edge. The notches are spaced to conform to the spacing of disks 46 on the cutting cylinder 41. The teeth 47 on each disk 46 of the cutting cylinder 41 pass through one of the notches 53 as the cutting cylinder 41 is rotated.

The teeth 47 are hook-shaped to insure positive engagement of each tooth with some of the waste as the cylinder is rotated in one direction. Each tooth carries some of the waste to the comb 52 and tries to push the waste through the notch 53. The notch 53 fits the tooth so closely that the waste projecting transversely of each tooth is cut off, and only the increment of waste fitting within the hook of the tooth is pushed through the notch to fall into the open top of discharge means 14.

The teeth 47 of the upper cutting cylinder 42 coact 31 .of the hopper. The peripheral surface of the cutting cylinder 42 is spaced so closely to the inner surface of the back wall of the housing 13 that no uncomminuted waste can pass through the gap between the cutting cylinder 42 and the back Wall of the housing. The lower end of the housing" is aligned withl'discha'rge' means 14.

The discharge means 14 comprises a bowl 55 having an open top defined by an annular flange 56 fitting against the underside of the housing 13 to which his secured in any suitable manner. The sides 57 of the bowl converge downwardly to an open lower end 58. The upper open end 59 of a water trap 60 is connected to the lower end 58 of the -'bowl'by a' clamp 61. The water trap is connected to a drain 62 in any suitable manner.

v'lhe'waste disposalunit is provided with a plurality of water jets,. hereinafter described, that are connected to the reserve water tank 15 and are operated by a pump (not shown), to facilitate passage of waste. The tank 15 insures anadequate supply of water to dispose of a complete load of waste whenever a cycle of operations is started. Two of the water jets, 63 and 64, are mounted adjacent the top of the hopper, two water jets, 65 and 66, are mounted at opposite sides of the housing 13, and two water jets, 67 and 68, are mounted in the discharge means 14. The functions of these various water jets will be hereinafter described in connection with the description of the operation of the entire waste disposal unit.

In the operation of the waste disposal unit, the hopper may be loaded piecemeal with individual bits of waste, such as discarded bandages, tape, etc., or the waste may be collected in a disposable plastic bag of suitable size, and the entire bag and its contents may be dumped into the hopper after the bag is filled. When the hopper is filled the cover is closed, and a starting switch on the control panel 26 is pressed to energize the electrical circuits (not shown) to actuate the motor 16 and the pump (not shown).

The motor 16 rotates both cutting cylinders in the same direction, counterclockwise as viewed in FIG. 2, so that the teeth 47 will bite into any waste which they come into contact with and carry the waste toward the comb adapted to cooperate with said teeth. The comminuting period is predetermined, and is normally from three to five minutes, after which the motor is automatically reversed to rotate both cylinders in the opposite direction for about half a minute to clean the combs. 7

At the same time the motor is in operation, the pump (not shown) forces water through each of the jets. The

' jets 63 and 64 may be mounted within the hopper, if

in a similar manner with a comb 54 that is secured to desired, but preferably are mounted in the cover 25 to avoid having any structure project inwardly of the walls of the hopper whereit might interfere with movement of waste through the hopper. The jet 63 throws a stream of water downwardly along the inner surface of the front wall 27 of the hopper. This stream of water helps to push any. waste that might lodge against the wall 27 downwardly into engagement with the cutting cylinder 41.

The jet 64 throws a stream of water downwardly along the inner surface of the vertical wall section 31 for a diflerent purpose. Although this water will also help move any waste adjacent the back wall of the hopper downwardly into engagement with the cutting cylinder 42, its primary function is to exert force against the waste adjacent the comb 54 andto move the waste in a direction opposite to the direction in which it is moved by the cylinder 42. The water from the jet 64 also sweeps the comb 54 to clean it. As shown in FIG. 2, the cylinder 41 is rotatably mounted in parallel relationship to the cylinder 42 but is in a lowerhorizontal plane. During the normal rotation of the cylinder, the cylinder 41and its teeth.47 move the waste engaged. thereby toward the comb 52 and the cylinder 42. Some of the waste is comminuted by the interengagement of the teeth of the cylinder 41 and the comb 52, and some of it is moved past the upper edge of the comb 52, where it is engaged by the cylinder 42 and its teeth. The cylinder 42 and its teeth move waste engaged by them toward the comb 54 where some of it is comminuted and is carried around on the cylinder until it drops into the open top of the discharge means 14.

Some of the waste being moved toward the comb 54 by the cylinder 42 is engaged by the water flowing downwardly along one surface of the comb, and is moved back toward the cylinder 41 against the action of that cylinder. This retrograde movement of the waste and the force of the water flowing downwardly from the comb 54 induces a rotational motion of the mixture of waste and water in the area above the comb 52. The direction of this rotational motion is opposite to the direction of the motion of the waste being moved toward the comb 52 and the cylinder 42 by the cylinder 41 and its teeth. The opposite rotational movement of waste and water in the area above the comb 52 causes the waste to present a constantly changing surface to the teeth of both cylinders, and thus facilitates comminution of the waste.

Some of the waste that is comminuted is cut so fine that it forms a powdery residue that is so light it does not fall into the discharge means, but is suspended in the mixture of water and waste that is being rotated opposite the direction of rotation of the cylinders.

When the rotation of the cylinders is reversed, the teeth no longer grab the waste, and the stream of water from the jet 64 washes the residual waste away from the comb 54. The streams of water from the jets 65 and 66, which keep the waste from bunching on the comb 52 during the initial period of rotation of the cylinders, wash the residual waste from the comb 52. The water from jets 63 cooperates with the water from jets 64, 65 and 66 to Wash the finely divided residual waste downwardly into the discharge means. The motor 16 and the pump (not shown) are both shut oflf after a reversal period of approximately thirty seconds. Both combs are clean and the hopper is ready for another load.

Although I have described a preferred embodiment of my invention in considerable detail, it will be understood that the description thereof is intended to be illustrative, rather than restrictive, as many details of construction may be modified or changed without departing from the spirit or scope of the invention. Accordingly, I do not desire to be restricted to the exact structure described.

What is claimed is:

1. A waste disposal unit comprising a supporting frame, a hopper supported by said frame, said hopper comprising four walls defining an opening at their lower ends, discharge means below said opening, at least two separate comminuting units mounted adjacent said opening, each of said comminuting units comprising a rotatably mounted cutting cylinder and a comb interengaged with each of said cutting cylinders and cooperating therewith to comminute waste, and means for rotating said cutting cylinders, one of said cutting cylinders being so positioned, relative to its comb and to said other cutting cylinder, that waste engaged by it and not interengaged by its comb is moved toward said other cutting cylinder, said cutting cylinders and combs being so positioned relative to said hopper and said discharge means that waste in said hopper passing through said opening engages one of said cutting cylinders and its related comb and is comminuted and then directed into said discharge means.

2. A waste disposal unit as recited in claim 1 in which each of said cutting cylinders has a length equal to the width of said opening and said cylinders are positioned sufficiently close to opposite walls of said hopper to prevent passage of uncomminuted waste between either cutting cylinder and the adjacent wall.

3. A waste disposal unit as recited in claim 1 in which said discharge means comprises a flushing bowl having an open top below and in alignment with said opening and in which said cutting cylinders and combs block the open top of said flushing bowl to prevent passage of uncomminuted waste from said hopper to said flushing bowl.

4. A waste disposal unit as recited in claim 3 and having jet means mounted in said flushing bowl to direct a stream of water adjacent the wall of said bowl to provide a swirling action to flush comminuted waste out of said bowl.

5. A waste disposal unit as recited in claim 1 and having means directing a stream of water along each comb to wash residue waste therefrom.

6. A waste disposal unit recited in claim 1 in which one wall of said hopper is inclined and terminates at said opening and one of said cutting cylinders is in alignment with said inclined wall, said waste disposal unit having a jet positioned to direct a stream of water down said inclined wall to carry waste downwardly along said inclined wall to said one cutting cylinder.

7. A waste disposal unit as recited in claim 6 in which the wall of said hopper opposite said inclined wall has a vertical section terminating at said opening, said waste disposal unit having a jet positioned to direct a stream of water down said vertical wall section, said second cutting cylinder being in alignment with said vertical wall section and being in a higher horizontal plane than said first mentioned cutting cylinder, the direction of rotation of said cylinders causing said first mentioned cylinder to move uncomminuted waste toward said second cylinder, and the water flowing down said vertical wall section moving uncomminuted waste from said second cylinder toward said first mentioned cylinder to continuously move uncomminuted waste in a circulatory path immediately above both of said cylinders to present constantly changing surfaces of said waste to said cylinders.

8. A waste disposal unit as recited in claim 1 in which said second mentioned means rotates said cutting cylinders in the same direction, whereby waste engaging one of said cutting cylinders and not moved into engagement with its comb is moved into engagement with said second cutting cylinder, said waste disposal unit having means directing a stream of water against said second cylinder to wash uncomminuted waste therefrom toward said first mentioned cylinder, the forces exerted against uncomminuted waste by said stream of water and rotation of said first mentioned cylinder causing uncomminuted waste to be rotated in a circulatory path adjacent said cylinders to present continuously changing surfaces to said cylinders.

References Cited UNITED STATES PATENTS 2,261,090 10/ 1941 Lind 241-46 2,453,006 11/1948 Feight 241-46 2,708,074 5/ 1955 Hoskins 24146 2,731,208 1/1956 Dodd 241-46 2,811,316 10/1957 Ewing 241-46 2,850,244 9/1958 James et a1 241-46 2,963,229 12/1960 Rhodes 241-46 GERALD A. DOST, Primdry Examiner. 

